Hey Vincenz!
Ahhh I apologize, I totally missed your bump.
It looks like the 'Send Reply' skill in your AI Agent somehow was not connected to the previous thread. I think there was an error somehow when setting it. I've deleted it and re-added it and it looks correct now.
Are you able to try again and let me know if you continue to have any issues? Thank you for your patience and apologies that I missed the followup here!